scholarly journals An integrated semigroup approach for age structured equations with diffusion and non-homogeneous boundary conditions

2021 ◽  
Vol 28 (5) ◽  
Author(s):  
Arnaud Ducrot ◽  
Pierre Magal ◽  
Alexandre Thorel
Keyword(s):  
Boundary Conditions ◽  
Integrated Semigroup ◽  
Semigroup Approach ◽  
Age Structured

Arrow-type sufficient conditions for optimality of age-structured control problems

2013 ◽  
Vol 11 (6) ◽  
Author(s):  
Vladimir Krastev
Keyword(s):  
Boundary Conditions ◽  
Sufficient Conditions ◽  
Control Problems ◽  
Infinite Time ◽  
Time Intervals ◽  
Sufficient Conditions For Optimality ◽  
Age Structured

AbstractWe consider a class of age-structured control problems with nonlocal dynamics and boundary conditions. For these problems we suggest Arrow-type sufficient conditions for optimality of problems defined on finite as well as infinite time intervals. We examine some models as illustrations (optimal education and optimal offence control problems).

scholarly journals Analysis of an Age-structured SIL model with demographics process and vertical transmission

2014 ◽  
Vol Volume 17 - 2014 - Special... ◽  
Author(s):  
Ramses Djidjou Demasse ◽  
Jean Jules Tewa ◽  
Samuel Bowong
Keyword(s):  
Vertical Transmission ◽  
Steady States ◽  
Asymptotically Stable ◽  
Basic Reproduction Ratio ◽  
Reproduction Ratio ◽  
Structured Population ◽  
Semigroup Approach ◽  
International Audience ◽  
Age Structured ◽  
Disease Free

International audience We consider a mathematical SIL model for the spread of a directly transmitted infectious disease in an age-structured population; taking into account the demographic process and the vertical transmission of the disease. First we establish the mathematical well-posedness of the time evolution problem by using the semigroup approach. Next we prove that the basic reproduction ratio R0 is given as the spectral radius of a positive operator, and an endemic state exist if and only if the basic reproduction ratio R0 is greater than unity, while the disease-free equilibrium is locally asymptotically stable if R0<1. We also show that the endemic steady states are forwardly bifurcated from the disease-free steady state when R0 cross the unity. Finally we examine the conditions for the local stability of the endemic steady states.

scholarly journals MHD Equations in a Bounded Domain

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maria B. Kania
Keyword(s):  
Boundary Conditions ◽  
Bounded Domain ◽  
Dirichlet Boundary ◽  
Base Space ◽  
Dirichlet Boundary Conditions ◽  
Mhd Equations ◽  
Semigroup Approach ◽  
Mhd System

Abstract We consider the MHD system in a bounded domain Ω ⊂ ℝ N , N = 2, 3, with Dirichlet boundary conditions. Using Dan Henry’s semigroup approach and Giga–Miyakawa estimates we construct global in time, unique solutions to fractional approximations of the MHD system in the base space (L 2(Ω)) N × (L 2(Ω)) N . Solutions to MHD system are obtained next as a limits of that fractional approximations.

Use of the Magnetostatic Analogue In Electromagnetic Lens Engineering

1970 ◽  
Vol 28 ◽  
pp. 360-361
Author(s):  
John W. Coleman
Keyword(s):  
Boundary Conditions ◽  
High Performance ◽  
Force Fields ◽  
Optical Design ◽  
Direct Conversion ◽  
Design Engineering ◽  
Design Data ◽  
Scalar Potentials ◽  
Geometric Elements ◽  
At Will

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.

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